This invention relates to multiple battery systems, and more particularly to rechargeable vehicle battery systems with a primary battery and a reserve or emergency battery that is connectable to a vehicle electric circuit in the event of primary battery failure.
Vehicle battery systems including a primary battery and a reserve battery for starting a vehicle in the event of primary battery failure are known. One such battery system disclosed in U.S. Pat. No. 5,108,848 includes a primary battery and a reserve battery disposed within a common housing. The reserve battery is selectively connectable in parallel with the primary battery through a manually operable switch or relay. A unidirectional charging circuit connects the reserve battery in parallel with the primary battery, permitting charging current to flow into the reserve battery, but preventing drain of the reserve battery during normal vehicle operation. When the primary battery output is insufficient to start a vehicle, the switch is manually operated to connect the reserve battery in parallel with the primary battery. The reserve battery provides sufficient power for the operator to start the vehicle. When the vehicle has been started, the switch is operated to disconnect the reserve battery from the battery circuit. The primary battery is charged in a conventional manner and the reserve battery is recharged through the unidirectional current circuit.
One drawback of prior art manually switched devices is that the reserve battery is engaged and remains engaged even after the vehicle is running if a user does not switch the reserve battery out of the circuit. Consequently, it is difficult for the user to determine whether or not the reserve battery is switched in with the vehicle electrical circuit or switched out. Thus, the originally isolated reserve battery is now subject to the same conditions as the primary battery and may fail along with the primary battery. Accordingly, the reserve battery may not be available to provide the needed starting capacity should the primary battery fail.
Another problem associated with such multiple battery systems involves the location of the manual switch. Typically, the manual switch is either located in the engine compartment or in the passenger compartment of the vehicle. Location of the manual switch in the engine compartment is disadvantageous, especially during inclement weather, or with persons not familiar with the engine compartment and its various components. Location of the manual switch in the passenger compartment can require extra wiring between the engine compartment (where the reserve battery is located) and the passenger compartment. This approach may not be practical in vehicles where the integrity of the firewall between the engine compartment and passenger compartment must be maintained. Accordingly, such hardwired systems may not be easy to retrofit into vehicles that have already been manufactured.
According to one aspect of the invention, a multiple battery system comprises a primary battery, a reserve battery electrically connectable to the primary battery, and a control unit with a relay switch electrically connected between the primary and reserve batteries. The relay switch is operable to close upon actuation and connect the reserve battery to the primary battery. The control unit also has a receiver electrically connected to the relay switch for receiving a control signal for actuating the relay switch. A transmitter is provided for sending the control signal to the receiver. With this arrangement, actuation of the transmitter causes the control signal to be transmitted to the receiver and actuate the relay switch to thereby connect the reserve battery to the primary battery.
According to a further aspect of the invention, a multiple battery system comprises a primary battery, a reserve battery electrically connectable to the primary battery, and a relay switch electrically connected between the primary and reserve batteries. The relay switch is operable between a closed position wherein the reserve battery is connected to the primary battery and an open position wherein the reserve battery is disconnected from the primary battery to prevent discharge of the reserve battery. A manually actuable switch is operably connected to the relay switch for moving the relay switch to the closed position upon actuation of the manually actuable switch. A timer circuit is operably connected to the relay switch for moving the relay switch to the open position after a predetermined time period.
According to an even further aspect of the invention, a method for temporarily providing reserve battery power to a vehicle having a primary battery and an electrical system connected to the primary battery is provided. The method comprises providing a reserve battery, providing a relay switch between the primary battery and the reserve battery, providing a manually actuable momentary contact switch in communication with the relay switch, actuating the momentary contact switch for a period of time to thereby connect the reserve battery to the primary battery for the period of time, and releasing the momentary contact switch at the end of the period of time to disconnect the reserve battery from the primary battery. Preferably, the electrical system comprises a starter motor, a starter solenoid and an ignition switch adapted for electrical connection to the primary battery. The ignition switch is actuated during the time period to thereby engage the starter solenoid and starter motor. In this manner, the reserve battery can start a vehicle with a discharged main battery.
According to an even further aspect of the invention, a method of conveying a battery back-up system to a customer is provided. The battery backup system has a reserve battery, a control unit connected to the reserve battery and a transmitter for actuating the control unit. The method comprises installing the reserve battery and the control unit in a vehicle to be conveyed, such that the reserve battery is connectable to a main battery of the vehicle through actuation of the control unit, offering the customer an option of purchasing the vehicle battery back-up system, giving the customer the transmitter for actuating the control unit if the customer desires the option, and keeping the transmitter from the customer if the customer refuses the option. In this manner, the reserve battery can only be accessed when the customer buys the option.